The cordless tool is convenient in that it is not tied to a power outlet. However, the battery capacity and its battery life did not suit me. When working, I had to have at least two batteries, while one was working the other on charging. During the day, I sat down as a minimum.
Then cadmium batteries needed to be charged only completely discharged, and lithium-ion, on the contrary, was afraid of a deep discharge.
The solution was found when I bought not large 6 volt lead batteries. And although the passport screwdriver is designed for 12 volts. Six volts was enough to screw the screws into 12 mm plywood (laid the floor), though he twisted them more slowly and with less effort (did not miss the plywood)
In order not to collective farm and not to disassemble the old battery, I just connected the wires to the terminals of the screwdriver. To do this, I used the wires from the washing machine with clamps, they easily dressed on the contacts of the device, and simply wound the wires to the Akum itself. And all this was fixed with a rubber ring - a piece from the car camera.
This summer I decided to buy a 12 volt battery. I picked it up so that it would be convenient to attach it to a screwdriver. After installation, the screwdriver surprised by the speed and power of rotation ...
Someone may say that lead batteries are heavier than lithium. I agree the old battery weighs about 500 g. Lead about 1.5 kg. Screwdriver without battery 1.7 kg. But at work this does not affect that 2 kg, 3 does not particularly affect. You only think about weight when you have to carry an instrument onto an object. Then every kilogram acts as drops of sweat on the forehead :)
It looks like this homemade in the video.
Ps. this is the first post on this site, do not judge hard and if that is not so - write.